leak-detective: Whitelist gcrypt_plugin_create()

gcry_check_version() does not free statically allocated resources. However,
we can't whitelist it in some versions, as it is not a resolvable symbol name.
Instead, whitelist our own plugin constructor function.

src/libstrongswan/utils/leak_detective.c

@@ -552,6 +552,7 @@ char *whitelist[] = {
 	/* ClearSilver */
 	"nerr_init",
 	/* libgcrypt */
+	"gcrypt_plugin_create",
 	"gcry_control",
 	"gcry_check_version",
 	"gcry_randomize",